Diabetes Risk could be Predicted by Blood Levels of Selenium
The selenium content of normal adult humans can vary widely. Values from 3mg in New Zealanders to 14mg in some Americans reflect the profound influence of the natural environment on the selenium contents of soils, crops, and human tissues. Approximately 30% of tissue selenium is contained in the liver, 15% in kidney, 30% in muscle, and 10% in blood plasma. Much of tissue selenium is found in proteins as selenoanalogues of sulfur amino acids; other metabolically active forms include selenotrisulphides and other acid-labile selenium compounds. The body needs selenium for normal growth and health. Selenium is needed for certain enzymes that help with normal body functions.
They are essential at low concentrations for maintaining cell-mediated immunity against infections but highly toxic if produced in excess.During stress, infection, or tissue injury, selenoenzymes may protect against the damaging effects of hydrogen peroxide or oxygen-rich free radicals.Although selenium is being used to prevent certain types of cancer, there is not enough information to show that this is effective. Selenium and vitamin E have been linked to possible prostate cancer prevention.
There have been several case reports of use of alpha-lipoic acid in combination with silymarin (milk thistle) and selenium (a substance with liver-protecting and antioxidant properties) to help treat hepatitis C (a serious type of hepatitis contracted from blood and bodily fluids that does not have an adequate cure or treatment).
Clinical manifestations of selenium deficiency arising from such situations are uncommon and poorly defined. They include muscular weakness and myalgia with, in several instances, the development of congestive heart failure. In at least one instance such pathologic signs have developed as a consequence of a generally inadequate diet providing selenium at less than 10mg/day.
When it comes to fertility and diet for men, a daily multivitamin that contains zinc and selenium for at least three months before conception may aid in healthy sperm development. Why the three-month lag time? It takes that long to develop healthy sperm.
Animal studies suggest that selenium, particularly in combination with vitamin E, may lower blood sugar levels over time and reduce the risk of complications (such as kidney and blood vessel diseases) associated with diabetes. Studies in people are needed before conclusions can be drawn.
The tolerable upper level is said to be 400 micrograms a day for adults, and the average U.S. diet contains about 100 micrograms a day, Deficiencies in selenium have been noted in HIV-positive patients, and evidence suggests that supplements of the nutrient can improve immune system function,
Contrary to researchers' expectations, high blood levels of selenium are positively associated with diabetes in adults, according to findings published in the medical journal Diabetes Care.
The results of some animal studies have suggested that oxidative stress reduces insulin secretion and increases insulin resistance, Dr. Joachim Bleys and colleagues from Johns Hopkins University Bloomberg School of Public Health, Baltimore, point out. They therefore hypothesized that because selenium has antioxidant properties, high levels of selenium in the body may prevent diabetes.
Selenium is a mineral required in small amounts to maintain good health. This mineral is necessary to generate antioxidant proteins that help prevent cell damage from free radicals, which are thought to contribute to the development of chronic diseases. Selenium also has a role in regulating thyroid gland function and the immune system.
To test their hypothesis, the researchers conducted an analysis of data from 8,876 subjects, at least 20 years of age, who participated in the Third National Health and Nutrition Examination Survey.
The team defined diabetes as a fasting blood sugar level of at least 126 milligrams per deciliter; patient reports of a physician's diagnosis of diabetes; or the current use of insulin or an oral diabetes medication.
The results of the study ran counter to what was anticipated. After accounting for the potential effects of age, sex, race, and weight, the researchers found that blood levels of selenium were 126.8 nanograms per milliliter in diabetics and 124.7 nanograms per milliliter in subjects without diabetes, a statistically significant difference.
Upon further analysis, the researchers found that subjects with the highest levels of selenium were 57 percent more likely to have diabetes than those with the lowest levels.
The authors call for more research to investigate high blood levels of selenium as factor that can increase the risk of diabetes.
Impaired fasting glycaemia (IFG) is a pre-diabetic state of dysglycemia, associated with insulin resistance and increased risk cardiovascular pathology, although of lesser risk than Impaired glucose tolerance (IGT). IFG may precede type 2 diabetes mellitus by many years.
There are 2 types of diabetes. Type 1 diabetes occurs when the body does not make a hormone called insulin. Insulin helps the body use glucose (a form of sugar) for energy. People with type 2 diabetes either do not have enough insulin or their cells ignore the insulin they have. Nearly 95% of people with diabetes have type 2 diabetes.
Until the findings of additional studies are available, increased levels of selenium, through the diet or in supplements, should not be recommended for diabetes prevention in individuals with normal selenium levels, Bleys and colleagues advise. "Furthermore, diabetic patients should avoid selenium supplementation" until evidence showing a benefit becomes available.
There is also some evidence that selenium may blunt the protective effect of statins in slowing cardiovascular disease, so patients on therapy for lipid disorders might wish to avoid selenium supplementation until there is better evidence that it is beneficial.